Heidar Helguson had two good attempts before the Eagles added a third goal in the 66th minute. Scannell's shot was parried by Loach but only as far as Danns who smashed the ball into the back of the net.

Cleverley hit the post again with a curling 20-yard shot before Watford substitute Danny Graham netted a consolation.

Lee Hills, who had earlier collected a booking for bringing down Lansbury in the first half, was sent off with three minutes left for a second yellow but Palace had done enough.

The victory keeps Palace in the relegation zone but to within a point of fourth-bottom Watford.